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(lib)unarr

(lib)unarr is a decompression library for RAR, TAR, ZIP and 7z* archives.

It was forked from unarr, which originated as a port of the RAR extraction features from The Unarchiver project required for extracting images from comic book archives. Zeniko wrote unarr as an alternative to libarchive which didn't have support for parsing filters or solid compression at the time.

While (lib)unarr was started with the intent of providing unarr with a proper cmake based build system suitable for packaging and cross-platform development, it's focus has now been extended to provide code maintenance and to continue the development of unarr, which no longer is maintained.

Getting started

Prebuilt packages

From OBS

.deb package .rpm package

Building from source

Dependencies

(lib)unarr can take advantage of the following libraries if they are present:

• bzip2
• xz / libLZMA
• zlib

CMake

mkdir build
cd build
cmake ..
make

... as a static library

cmake .. -DBUILD_SHARED_LIBS=OFF

By default, (lib)unarr will try to detect and use system libraries like bzip2, xz/LibLZMA and zlib. If this is undesirable, you can override this behavior by specifying:

cmake .. -DUSE_SYSTEM_BZ2=OFF -DUSE_SYSTEM_LZMA=OFF -DUSE_SYSTEM_ZLIB=OFF

Install

make install

Testing

Unarr supports unit tests, integration tests and fuzzing.

cmake .. -DBUILD_UNIT_TESTS=ON -DBUILD_INTEGRATION_TESTS=ON

To build the unit tests, the cmocka unit testing framework is required.

Building the integration tests also enables the unarr-test executable which can be used to run additional tests on user-provided archive files.

Building the fuzzer target will provide a coverage-guided fuzzer based on llvm libfuzzer. It should be treated as a stand-alone target.

cmake .. -DBUILD_FUZZER=ON

All tests can be run using ctest or their respective executables.

Usage

Examples

Check unarr.h and unarr-test to get a general feel for the api and usage.

The unarr-test sample application can be used to test archives.

To build it, use:

cmake .. -DBUILD_INTEGRATION_TESTS=ON

Limitations

Unarr was written for comic book archives, so it currently doesn't support:

• password protected archives
• self extracting archives
• split archives

7z support

7z support for large files with solid compression is currently limited by a known performance problem in the ANSI-C based LZMA SDK (see zeniko/unarr#4).

Fixing this problem will require modification or replacement of the LZMA SDK code used.

Rar support

RAR5 is currently not supported. There are plans to add this in a future version, but as of now this is still work in progress.